The present invention is directed to electromagnetic shielding. To meet FCC and other regulatory agency EMI (electromagnetic interference) compliance requirements it is necessary to control propagation of EMI from a product with appropriate shielding. The ideal shield would be a continuous conductive metal box around the source field. It is desirable, however, to break this shield to provide slots for cooling and removable panels for assembly, test, and service. Breaking the continuity of the shield with an elongated opening reduces its effectiveness.
The allowable length of the elongated opening is dependent upon the frequency of the source field. To maintain shielding effectiveness as the source frequency increases, the allowable slot length becomes shorter. While a ground strap from a chassis to a conductive panel may provide adequate shielding effectiveness for one product, there are other products which require periodic contact between the conductive panels and the chassis.
In a volume product, the requirement of repeatable periodic contact between the conductive metal chassis and removable conductive panels must be met in a cost-effective manner. Fasteners are reliable but labor-intensive. Adhesive-backed contact devices are labor-intensive, difficult to locate repeatedly and unreliable. Devices that slip onto an edge have limited application and seem to slip off as easily as on.
U.S. Pat. No. 4,554,400 (Schmalzl) discloses a metal clip that has a nose portion and two end tabs. The nose portion fits into a slot in a conductive plane and holes are provided on either side of the slot for inserting the tabs to hold the clip in place. The nose portion may also be bent to assist in holding the clip in its position.
It is an object of the present invention to provide an electromagnetic shielding clip that can be easily inserted and securely held within a single slot in a conductive panel.